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VEGF‐induced paracellular permeability in cultured endothelial cells involves urokinase and its receptor
Author(s) -
Behzadian M. Ali,
Windsor L. Jack,
Ghaly Nagla,
Liou Gregory,
Tsai NaiTse,
Caldwell Ruth B.
Publication year - 2003
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fj.02-0484fje
Subject(s) - urokinase receptor , occludin , paracellular transport , vascular permeability , microbiology and biotechnology , chemistry , vascular endothelial growth factor , downregulation and upregulation , angiogenesis , receptor , tight junction , biology , endocrinology , permeability (electromagnetism) , cancer research , biochemistry , membrane , gene , vegf receptors
Vascular endothelial growth factor/vascular permeability factor (VEGF) has been implicated in blood/tissue barrier dysfunctions associated with pathological angiogenesis, but the mechanisms of VEGF‐induced permeability increase are poorly understood. Here, the role of VEGF‐induced extracellular proteolytic activities on the endothelial cell permeability increase is evaluated. Confluent monolayers of bovine retinal microvascular endothelial (BRE) cells grown on porous membrane were treated with VEGF or urokinase plasminogen activator (uPA), and permeability changes were analyzed. uPA‐induced permeability was rapid and sustained, but VEGF‐induced permeability showed a biphasic pattern: a rapid and transient phase (1–2 h) followed by delayed and sustained phase (6–24 h). The delayed, but not the early phase of VEGF‐induced permeability, was blocked by anti‐uPA or anti‐uPAR (uPA receptor) antibodies and was accompanied by reduced transendothelial electrical resistance, indicating the paracellular route of permeability. Confocal microscopy and Western blotting showed that VEGF treatment increased free cytosolic β‐catenin, which was followed by β‐catenin nuclear translocation, upregulation of uPAR, and downregulation of occludin. Membrane‐bound occludin was released immediately after uPA treatment, but with a long delay after VEGF treatment, suggesting a requirement for uPAR gene expression. In conclusion, VEGF induces a sustained paracellular permeability in capillary endothelial cells that is mediated by activation of the uPA/uPAR system.